Signal level raiser



4 Sheets-Sheet 2 Filed Jan. 19, 1928 1N VENTORS S IGNAL LEVEL RAI SER 4 Sheets-Sheet 3 Filed Jan. 19,l 1928 INVENTORS Q mq@ m@ www Q @awa ..1 L L nu mm M www www@ uw mw nah w .ANN

250. HADA\\ in m April 26, 1932.

2&0. 'RADlANT ENERGY.

Apr-i126, 1932. B. WASHINGTON ET Al. 1,856,009

SIGNAL LEVEL RAISER Filed Jan. 19, 1928 4 Sheets--Shee'fI 4 INVENTORS ORNEY Patented Apr. 26, 1932 4 UNITED STATES PATENT OFFICE BOWDEN WASHINGTON, OF NEW YORK, .AND 'WILSON AULL, JR., OF ASTORIA, NEW

YORK; DOROTHY CLINTON WASHINGTON,

ADMINISTRATRIX OF IBOWDEN WASHING- TON, DECEASED, ASSIGNORS TO REMOTROLE CORPORATION, A CORPORATION OF NEW YORK SIGNAL LEVEL BAISER Application led January 19, 1928. Serial No. 247,880.

One object of our invention is to raise the signal level of all Signals within a given frequency band over a considerable area. I

Another object is to produce a device which will enable residenxtsdpLa/hotelgapartment housegoncommunity to .enj oy a Ywideaig'gle of programsfrom both distant and local stations by the use`"6f` simple and inexpensive receivers.

Another object is to improve the reception of a large number of stations in an area where receiving conditions are ordinarily poor.

Broadly we propose to pickup all available signals within a predetermined band, regulate said signals so that their intensities are of the same order of magnitude, andre;- broadcast t .reatlyampliiied but without change in carrier fre ulei s. These greatlystrengthened signals may then be received over short to moderate ranges on simple and inexpensive receiving apparatus.

Referring to the dra-wings, Fig. 1 is diagrammatic view of one form of our invention.

Figs. 2, 3, and 4 show systems for regulating the sensitivity of our device to certain chosen frequencies.

Fig. 5 shows a schematic wiring diagram of one embodiment of our invention.

Fig. 6 shows a schematic wiring diagram of another embodiment.

In Fig. l, l0 and 11 constitute a antennasystem. l2 is a sensitive amplifier preferbly of the band-pass type desigfl-to cover t`h\e frequencies itis desired to rebroadcast`` 13 `i`i`te`redia`tpower amplifier whose inputis connected to the output'of 12 and whose output is connected to the input of the full power amplier 14 which may use an anode power of the order of 1000 watts or more if desired. The amplifiers 13 and 14 should be of the untuned or band-pass type. The amplier 14 isvidlwithvtheradiating means l5 and 16. It is preferable that this cascade of amplifiers be so designed that there is a 90 phase difference between the input and the output to prevent over-all regeneration or degeneration. This phase difference may be produced in any well known manner, for instance, by proper selection of interstage coupling means. 17 represents a frequency meter having the variable condenser 18 and the quantitative current indicator 19. 2D`represents-a`tuner and rectifier and may be provided with the head receivers 21. This tuner-rectifier may be loosely coupled with the amplifier l2 and may be used by the operator as means to check up the intensities pfjaniogsgincominev sigalswhile the frequency meter ll'iay e used to deter' mine the relative amplitudes of rebroadcast signals. """m-F' All signals throughout a given predetermined band are thus received by the i'eceilgfing antenna s stem 0 mLll ampli ed the ampnsfsymid 14 and .wahoni change of carrier frequency or side bands rebgoadcasngreatly-strengthened by the antenna system- 1 5fand16.

It should be noted"that experiment has shown that even though some of the received signals have a fairly strong eld strength before amplification, the interference pattern between the signals proper and the rebroadcast signals changes at an inaudible rate so that no weak or dead spots will occur.

In Fig. 2, 25 indicates the entire amplification system having an antenna 10 and a ground 11. 26, 27, and 28 indicate resonant circuits which may be variably coupled to the inductances 29, 30, and 31 which are included in series with the antenna. These are commonly known as coupled rejector systems and their purpose is by means of the well known anti-resonant effect to suppress to varying degrecs signals of high intensity so that the rebroadcast signals shall all be of the same generalorder of magnitude.

Figs. 3 and 4 show other means of accomplishing the same result, in Fig. 3 by the direct by-pass circuits 35, 36, and 37 and in Fig. 4 by the variably coupled blocking cir- 56 in series with the antenna system. These tubes are coupled by the resistors 57 and 58, and the condensers 59 and 60. The grid leaks 61 and 62 are also provided. A negative bias of the grids is obtained by the resistors 63, 64, and 65. Radio frequency by-pass con` densers of the anode circuits are shown at 66, 67, and 68.

A multi-cell band-pass filter`may be provided at being so designed as to pass the desired band of frequencies and havinO' a high impedance to frequ-encies without thisband so as to prevent the passage and amplication of unwanted signals and reduce to a minimum the amplification of static and other interference.

Following this band-pass filter is the three'- stage resistance coupled amplifier employing the tubes 71,72, and 73 which is similar to the amplifier 52 with the exception that tubes of higher capacity and a higher anode voltage may beemployed. 74C is a resistance coupled radio frequency amplifying tube of still higher capacity while 75 and 7 6 represent two still larger tubes used in parallel for the final or output stage and having in their output circuit an inductance or resistance 77 used as a means of coupling the antenna system 78 and 79. The direct current generator 80 acts as a common source of anode power for all of the tubes and may be provided with a lter consisting of the inductance 81 and condensers 82 and 83. The anode voltage for the various tubes may be regulated by the insertion of suitable resistors as 84, 85 and 86.

' 104 and condensers as 105 and 106. In this amplifier the cathodes are heated by alternating current derived from the line 107 108 by means of the transformers 109 and 110. Anode power is derived from the transformer 111 in conjunction with the rectifiers 112 and the filter 113. The magnitude of the voltage applied to the various tubes is regulated by the resistors such as 114 and 115, while grid bias is obtained from the resistors such as 116 and 117.

By means of our invention satisfactory distribution of a large number of programsinay be effected to y individual listeners equipped with simple andineXpen/sivereeivers. For headphone reception over midfeate distances; axreceiver containing a single tub`e`could be used, while loudsiiler recepti'iild be had with a detector and two audio frequency stages of amplification.

This means of distribution gives the listener a much larger choice of rofframsjhan could be halwitli a sys em emp oying wire 1n`e`s, wh'eiermless-can'ercurrents'd'r attendant complications be employed, a sepai'ate line must be installed for each station whose program is attainable. Also if any considerable area is to be covered the expense of a large number of lines would be prohibitive.

By'meaiis of our invention a hotehpould sup l simple'receiverstnnts Hguggs at a nomina `r e"i"italantl'tliiis pziyLfmnth@ upkeep of the band`rb`fd'c-a-s'ter.

It willbesithatour invention d-i-Ee-rs from what is commonly termed rebroadcasting for we amplify and itrarjsuiLLlarge number p fffrequeicieswwitlit'changepf frequenlzy.V Rebroa'dcasting'heret'fce has consisted of receiving at one frequency and retransmitting the modulations of the received wave on another frequency, thus employing two channels, while in our system no additional channels are employed, and no interferenceisreatedl'm"' ive/claim:

1. A method of simultaneously increasing the field strength of several rali q ghannels over a continuous bandf-fequencies which consists in collecting said signals, amplifyinggthem, and retransmittino' them at their original respective frequencies but at such ,t

a phase as to plifier. l

2. An apparatus for simultaneously inl creasing the field strength of all signals within a broadcast band of frequencies which consists of an untuned receiving antenna system, an untuned radio frequency amplifier system, whose input is associated therewith, an untuned radio frequency power amplifiersystem, having an untuned transmitting antenna system, and a band pass filter interposed between said radio frequency amplifier systems.

3. An apparatus for simultaneously increasing the field strength of all of the signals of various frequencies within a predetermined frequency band without change in the respective frequencies of said signals which consists of a broadly tuned signal collector associated with the input of a .sensitive untuned radio frequency amplifier whose output is connected to the input of an untuned power amplifier, said latter amplifier having associated with its output an untuned radiating system.

4. As a means for simultaneously increasing the intensity of a number of radio signals of widely differing frequencies, a vacuum tube band-pass amplifier having receiving means sensitive to a predetermined band of frequencies, and radiating means adapted to radiate said predetermined band and means for equalizing the signal strength of prevent retroaction in the am,`

aso. Ranieri* I /ye/ various signal frequencies, said amplifier employing vacuum tubes of higher power capacity at its output than at its input. y

5. An apparatus Whose object is to allow the choice and reception of a large number of broadcast programs at a number of receiving stations equipped with relatively simple apparatus which consists of a band-pass radio frequency amplier having sensitive input stages and power output stages, said amplifier having a pick-up device capable of responding to all signals within a broad band of frequencies, and a radiating device capable of transmitting the same band With substantially uniform strength in all direct-ions but with a 90 phase relation to the input.

6. A device for enabling a number of listeners to receive distant stations on relatively insensitive apparatus which consists of a pick-up device capable of being excited by any frequency Within a predetermined broadcast band, means for equalizing the strength of the various received signals, an amplifier responsive to said band. and a radiator adapt- 0 pressing any undesired frequency and means for radiating all of said amplified signals at their received frequencies and in all directions.

9. A broadcast signal strengthening system comprising means for picking up and amplifying all signals Within the standard oroadcast band, means for modifying the relative intensities of selected signals, and means for radiating all of said amplified signals at their received frequencies but at such a phase relation with respect to the pick-up as to prevent interference.

l0. Apparatus of the character described comprising means including an antenna system for picking up all available broadcast signals Within a predetermined band of frequencies, means for regulating the received signals and bringing them to substantially the same order of magnitude, means for amplifying the received signals Without change 1n carrier frequency or side bands and means including an antenna system for radiating all the amplified signals but with an approximately 90 relation between the electro-static and electro-magnetic fields of the input and output antenna systems.

11. In a system as described, input means for receiving all the signals Within the normal broadcast band, a multi-cell band pass filter for eliminating interference, a multistage amplifier, output means for radiating the output Without change of frequency and means for preventing interference between the output and input.

- BOWDEN 'WASHINGTON WILSON AULL, JR. 

